1. Field of the Invention
The present invention relates to an opening/closing device for an upper unit case which is installed to be rotatable in an opening/closing direction with respect to a lower unit case. More specifically, the present invention relates to construction of an opening/closing device, for an upper unit case, in which the upper unit case is configured to be movable slowly in a closing direction thereof, and an image recording apparatus provided with the opening/closing device for the upper unit case.
2. Description of the Related Art
Conventionally, in an image recording apparatus such as a printer, a facsimile machine, a copying machine, etc., a paper feeding section (sheet feeding section), a recording section, etc. are provided on a lower unit case. On the other hand, a manuscript (original) reading section is provided on an upper unit case. A hinge is provided on the upper case at one side thereof, and the upper unit case is installed to the lower unit case so that the upper unit case is rotatable via the hinge in the opening/closing direction. There are proposed various kinds of construction for regulating the rotating movement of the upper unit case in a closing-movement finishing zone of the rotation of the upper unit case in a case that the upper unit case is once widely opened during maintenance and/or addressing paper jam situation, etc. and then the upper unit case is to be closed.
For example, Japanese Patent Application Laid-open No. 11-38714 (FIGS. 1 and 2) discloses an opening/closing device in which an upper unit case and a lower unit case are connected by a gas spring, and a coil spring is arranged on the lower surface of the upper unit case at an free end side so that the coil spring is oriented downwardly. An end of the coil spring is supported at a receiving section in the lower unit case, in the closing-movement finishing zone, thereby preventing the upper unit case from being closed abruptly.
On the other hand, Japanese Publication of Registered Utility Model Application No. 01-29815 (FIGS. 3 and 6) discloses an opening/closing device in which an arc-shaped guide member (guide member) is formed on a side surface of an upper unit case (cover) so as to project downward, and an arc-shaped guide groove is formed in the guide member. Here, a bolt shaft is disposed at one side of a lower unit case (casing). By inserting the bolt shaft into the guide groove and by pinching (sandwiching) the guide member by the head of this bolt and a spring member, it is possible to position and hold the upper unit case at any rotational angle. Further, Japanese Publication of Registered Utility Model Application No. 01-29815 discloses a technique in which, when the upper unit case is at a position at which the upper unit case is closed (stopped and closed) with respect to the lower unit case, the upper unit case is urged upwardly by a torsion spring provided on the lower unit case.
In the above-described closing/opening devices, however, the number of parts or components are large, and a part or component having a large size such as the gas spring is required. It is also considered to provide a linear-shaped oil dumper, instead of the gas spring, or to add a rotary oil dumper to the hinge section so as to make the velocity be slow when the upper unit case is closed with respect to the lower unit case. By doing so, however, there is generated a problem such that the construction of the opening/closing device becomes more complex and/or the ratio of the opening/closing device to the entire product such as the lower unit case become greater, which in turn causes the product size to become greater.
An object of the present teaching is to simply and to make small the parts or components constructing the opening/closing device, and further to make the closing operation or movement of the upper unit case to be light and quick. Another object of the present teaching is to provide an image recording apparatus which is provided with the opening/closing device.